Portable steam-engine



(No Model.)

J. H. ELWARD.

Portable Steam Engine. No.'239,375. Patented March.29 ,188l.

N-PETERS. PHOTO-LITHDGRAFHER. WASHING'ION. I?!v C UNITED STATES PATENT OFFICE.

JOHN H. ELWARD, OF STILLWATER, MINNESOTA.

PORTABLE STEAM-ENGINE.

SPECIFICATION forming part of Letters Patent No. 239,375, dated March 29, 1881. Application filed January 28, 18 81. (No model.)

To all whom it may concern:

Be it known that :1, JOHN H. ELWARD,a citizen of the United States, residing at Stillwater, in theeounty of Washington and State of Minnesota, have invented certain new and useful Improvements in Steam-Engines; and I do hereby declare the following tobe a full, clear, and exactdescription of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or figures of reference marked thereon, which form a part of this specification.

Figure 1 is a side elevation of an engine embodying my improvements. Fig.2 is aside elevation of the feed-water heater and parts of the water-pipe and exhaust-steam pipe. Fig. 3 is a perspective of a casting, having the parts from which are formed the steam-chest, the cylinder, the heater, and the pillow-block for the shaft all in one piece. Fig. 4: is a view illustratinga modification of the relief mechanism. I

The parts to be hereinafter described may be combined with an engine of any suitable charactenthough many of them are especially adapted foruse in traction or portable engines.

In the drawings, A represents the cylinder, and B the steam-chest. The steam passes thereto,in the ordinary manner, through the pipe H from the dome G, the passage being controlled by means of the valve at H and the governor at I.

G 0 represent the-upper and lower guides for the cross-head K of the piston Q. The guides O O are attached to the heating-box D by means of brackets F. p

L is the pitman, and m the crank-wheel attached to the engine-shaft M The shaft is mounted in the pillow block or standard E attached to the heating-box.

To have the movable parts of an engine workgproperly it is necessary that the piston,

the cross-head, and the shaft-bearing should always be in the same position relativeto each other. Whenthe various parts of the engine are constructed in separate pieces this exactness of relative position cannot be permanently o preserved, as is well known, for if one of the above-mentioned parts, by straining or jarrin g,

be thrown into an improper position relative to the others the working of the engine is seriously interfered with. In order to avoid all such variations in relative position, I have devised a casting which contains all of the parts necessary for a cylinder, a steam-chest,

a guideway, a heating-box, and shaft-support in one piece, so that it is impossible for the valves, the cylinder, the guides, or the shaft to be ever thrown out of their'proper working positions. The guides G O are arranged to be one above and the other below the crosshead. The inner 0r guidingsurfaces describe portions of a cylinder concentric with the cyl-1 inder-A. They areconnectedby means of brackets c c. As the surfaces of the guides are concentric with the cylinder, the cylinder and the guides are, after casting, bored by one continuous operation from one end of the cylinder to the opposite end of the guides, the absolute concentricity of these. parts being thus attainable.

The steam-chest B is cast in one piece with the cylinder, the side opposite to the cylinder being cast open to permit the ready planing of the working-surfaces therein. When thus constructed the ports and valves cannot get out of proper position relative to the cylinder.

The heating-box D is also cast in one piece with the parts above described, it being situated directly beneath the steam-chest and connected to the guides O O by means of brackets F F. When thus arranged the heating- 8 5 box provides a permanent bed for the other parts of the engine, so that whether the box vary in position relative to the boiler or not, the other parts cannot vary relative to the box or bed.

The pillow-block or standard E for the shaft is cast in one piece with the heating -box. When the shaft is mounted thereon the paths in which the pitman. and the eccentric-rod move are always the same. 5

The interiors of the box and of the other hollow parts are formed by means of cores.

The cross-head K is arranged vertically, and

the convex blocks 70 are fitted to the surfaces of the guides. The cross-head carries a downwardly-projecting stud, P.

V N represents the pump, placed below and parallel to the cylinder, the piston-rod O of which is connected to and operated by the stud P. The water is drawn from the tank through the pipe (preferably made of flexible hose) W and forced through the pipe Rto the heating-pipe S. There is a valve, T, by which some or all of the water from the pump may be forced into the pipeV, (also preferably made of flexible hose,) through which it may be either returned to the tank or maybe used for cleansing the boiler or extinguishing fires, 850. The heating-pipe S passes through the heating-box D, and as the water passes through said pipe it'is heated by the exhaust-steam from the cylinder.

Heretofore it has been customary'to pass the exhaust-steam from the cylinder into the heating-box at the end nearest the cylinder, and to withdraw the same from the box at the same end; and it has also been customary to construct the heating-box with longitudinal partitions to carry the steam from the end near the cylinder to the opposite end and then back before it is permitted to escape through the exhaust-pipe. When a construction of the first class is used the exhauststeam delivers but a small part of its heat before it escapes from the box. Many serious difficulties are experienced in constructing heating boxes of the other kind mentionedthat is, boxes with longitudinal partitions. There is so great a difference between the contractin g and expanding of the outside parts of the heater and the contracting and expanding of the partition that, it has been found to warp and break in a comparatively short time. The partitions are necessarily made thin, and, be-

ing totally surrounded by the intensely-heated steam, are subjected to conditions of contraction and expansion greatly differing from those of the outside parts, which are affected upon one side by the steam and upon the other by the air. As stated above, it has been found that the almost unavoidable result is the destruction of the partition. Moreover, the construction of the heating-box with these partitions is a matter of great expense and difficulty, owing to the necessity of the use of cores in the casting, and many are ruined in the manufacturin g. I have succeeded in avoiding these difficulties by constructing theheater and pipes as shown. The heatingbox is situated horizontally, and is made as long as possible. The exhaust-pipe Z extends almostthe whole length of the box and receives thesteam at the end op posite to the cylinder. The feed-pipe S passes straight through the box, without the joints or couplings ordinarily used inside of the box. The steam from the cylinder is compelled to envelop entirely that portion of the pipe S within the box and to pass along the'whole length thereof before entering the exhaustpipe. The pipe S may be made very thin, as it is not afiected by the expansion or contraction of the outer parts.

When the exhaust-steam is used to create a draft in the smoke-stack it is necessary to reduce the escapeorifice in order to produce a sharp draft, a reduction to one-half of the usual diameter being often necessary. This causes a strong back pressure in the engine. It is generally necessary to use this sharp draft only a short time, and then the pressure should be relieved as soon as possible. To effect this I have combined with the heatingbox a relief-valve.

D is a short pipe projecting downwardly from the box. G is a lateral extension thereof, and W represents a lower pipe communicating with the latter.

K is a valve fitted to a seat formed in the pipe. It is supported upon a rod or stem, L, to which itis attached. Bearings for the stem or rod are provided in the parts B and L 1 is a cap covering the open end of the pipe G, and attached thereto by a screwthread. It may be either rigidly connected with the part B or formed independently thereof. A spring, M, is placed around the stem L and bears against the valve K and the part B. By means of the parts R and I the tension of the spring may be increased or diminished, and in this way the resistance of the valve may be adjusted. A portion of the steam is permitted to escape by the valve when there is a back-pressure from the exhaustpipe, thus relieving the engine of pressure.

0 represents a drip pipe communicating with the heating-box and with the pipe N below the valve K. It is provided with a valve at P.

The water passes to the boilerfrom the heating-pipe S in the usual manner, the pipe having the ordinary valves at E and F.

What I claim is- 1. The combination of the following elements, viz: a portable horizontal boiler, the heating-box D, secured to the side of the boiler and having a single continuous chamber, the water-pipe S, passing directly through said box, the cylinder arranged to discharge steam into said box at one end thereof, and the exhaust-pipe Z, passing into the box D, and havin g a portion lying therein nearly equal in length to that of the box, whereby it removes the steam from the end opposite to the cylinder, as set forth.

2. The combination, with the cylinder and the devices which conduct the exhaust-steam therefrom, of an automatic valve arranged, substantially as described, to be opened directly by the pressure of the steam against it to relieve the engine of back-pressure from the exhaust mechanism, as set forth.

3. The combination, with a horizontal portable boiler, of the herein-described engine and engine-bed secured in one piece to the side of the boiler, said engine and engine-bed consist- ICO ing of the heating-box 1), arranged as a bed In testimony whereof I affix my signature for the engine, the steam-chest B, the guides in presence of two Witnesses. G C, the cylinder A, of the same internal diameter as the guides O O, the pillow- JOHN H. ELWARD. 5 block E, and the brackets F, all secured to V gether without joints, and all removable to- Witnesses:

gether from the boiler, as and for purposes set R. W. CHAMBERS,

forth. ALFRED KEEVIL. 

